A must-read piece by the Associated Press yesterday took a deep-dive into how PRISM fits into the wider context of US online espionage programs. The AP reports that PRISM acts as a kind of refining tool for data that the National Security Agency (NSA) pulls data from the undersea cables that pipe Internet data in and out of the USA:

“Prism appears to do what its name suggests. Like a triangular piece of glass, Prism takes large beams of data and helps the government find discrete, manageable strands of information.

“The fact that it is productive is not surprising; documents show it is one of the major sources for what ends up in the president’s daily briefing. Prism makes sense of the cacophony of the Internet’s raw feed. It provides the government with names, addresses, conversation histories and entire archives of email inboxes.”

The report, considers whether data gleaned from technology companies via PRISM allows the NSA to navigate through the enormous bulk dump of Internet data it collects from the undersea cables.

“For example, not every company archives instant message conversations, chat room exchanges or videoconferences. But if Prism provided general details, known as metadata, about when a user began chatting, could the government “rewind” its copy of the global Internet stream, find the conversation and replay it in full?”

In other words, technology companies may be telling the truth when they say that they only hand over specific user information in response to specific requests, but the NSA doesn’t really need anything more from them anyway, because they already have a ‘raw feed’ of Internet traffic to pull from.

Elsewhere, the Washington Post reports that PRISM works with three other programs run by the NSA; MAINWAY, MARINA and NUCLEON. Together, the programs collect vast swathes of metadata about telephone and Internet communications passing through USA.

“When the NSA aims for foreign targets whose communications cross U.S. infrastructure, it expects to sweep in some American content “incidentally” or “inadvertently,” which are terms of art in regulations governing the NSA. Contact chaining, because it extends to the contacts of contacts of targets, inevitably collects even more American data.”